Current intra-oral dental sensors suffer from several drawbacks that manufacturers would like to circumvent.
They are often uncomfortable for the patient because of the sharp angles of the casing which tends to follow the rectangular shape of the silicon sensor that it contains. The constituent material of the casing is hard, for essential mechanical strength reasons, and somewhat unpleasant in terms of sensation in the mouth. The hardness of the material is required in practice so that the internal electronic circuits in the casing are protected from shocks (for example should it be dropped) by a sheet of foam or elastomer interposed between the electronic circuits and the wall of the casing, or even by sheets of other materials having additional functions (aluminum foil or lead foil).
The sensors are most often black, a color which is unpleasant to the user's or even the practitioner's eyes. In this field, white would instead be expected, the usual color of medical apparatus symbolic of cleanliness. However, if the sensors are made white, or even colored, the risk of producing an undesirable image because of the ambient light would be high. This is because the casing is necessarily thin for size reasons, and is therefore relatively transparent, and the lighting in a dental practitioner's surgery is often very strong. In the absence of X-ray illumination, a non-black image would then appear on the screen placed in front of the dental practitioner or even in front of the patient—such a meaningless image is unwanted and ought not to appear, so as not to trouble the patient or the practitioner.
Since the casings are all black and geometrically very similar, the various manufacturers cannot easily differentiate their products from those of competitive manufacturers. However, manufacturers, and moreover purchasers too, wish to differentiate their products and those of their competitors, which differentiation is difficult if all the sensors are black, of the same shape and the same size.
More generally, the market for these sensors is demanding improvements in terms of comfort and ergonomics.
The objective of the present invention is to take into account these many constraints and to produce an intra-oral dental radiology image sensor which, without impairing the image acquisition functionality, is more pleasant in one's mouth and more pleasant to the eye, while at the same time being distinctive, strong and optimally protected from shocks.
To achieve this objective, the invention proposes an intra-oral dental radiology image sensor comprising an electronic image acquisition module and a molded casing made of a hard plastic, characterized in that the casing locally includes overmoldings made of a soft plastic having the consistency of smooth rubber, at least over the sharpest corners of the hard plastic on the outside of the casing and in internal areas of the hard plastic at places where the electronic module may bear.
The shape of the hard plastic part and the shape of the overmolded soft plastic on the hard plastic are defined in such a way that the outside of the casing is free of asperities, notably at transitions between overmolded soft plastic areas and overmolding-free hard plastic areas.
The hard plastic may be a semicrystalline material such as a polyamide. The softer plastic may be a copolymer of the SEBS (styrene/ethylene-butylene/styrene) type.
These plastics may be easily overmolded together by injection molding. The softer plastic is preferably white or colored. It may be printed with a design or with characters.
In one particular embodiment, the casing includes a projecting dome through which an electrical cable passes, and this dome consists only of the soft plastic.
In another embodiment, one part of the shell is specifically intended to form an area sensitive to the touch for the practitioner's finger so as to help him to position the sensor in the patient's mouth. This specific sensitive area is coated with the soft plastic having the consistency of smooth rubber.
Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious aspects, all without departing from the invention. Accordingly, the drawings and description thereof are to be regarded as illustrative in nature, and not as restrictive.